Device for separation of oil, ventilation system, cylinder head cover and internal combustion engine

ABSTRACT

A device for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine. Also described is a ventilation system for ventilation of the crankcase of an internal combustion engine, a cylinder head cover and an internal combustion engine, which contain such a device.

The present invention relates to a device for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine. Furthermore, it relates to a ventilation system for ventilation of the crankcase of an internal combustion engine, a cylinder head cover and an internal combustion engine, which include such a device.

In the crankcase of an internal combustion engine, blow-by gases occur, which are guided normally, in particular for environmental reasons, into the intake duct of the internal combustion engine. It must thereby be ensured that the pressure applied in the crankcase is maintained within the narrow required upper and lower limiting values. For this purpose, the blow-by gases are discharged out of the crankcase via a ventilation pipe, for which purpose the pressure difference between the crankcase and the intake duct of the internal combustion engine is used.

A ventilation system for a crankcase for transporting blow-by gases therefore normally has a ventilation pipe from the crankcase to the intake duct of an internal combustion engine. In the ventilation pipe, generally an oil separator/oil mist separator is disposed furthermore in order to separate oil and oil mist, which are contained in the blow-by gases, from the blow-by gases. For this separation, likewise the pressure difference between the crankcase and the intake duct is used. This means that the pressure difference between the intake duct and the crankcase is used suitably for throughflow of an oil separator/oil mist separator and therefore is likewise subject to certain limits. In particular, the ventilation must be controlled such that, on the one hand, the occurring blow-by gas flows are discharged safely and, on the other hand, the pressure decrease over the oil separator is within an optimum range for efficiency of the oil separation.

In particular in the case of internal combustion engines with supercharger device/compressor, for example a turbocharger or a compressor, and also a throttle valve, different pressure ratios which depend upon the operating state of the internal combustion engine occur in different sections of the intake pipe between the air filter and the inlet valve of the engine for fresh air.

In full load operation, a very high pressure which cannot be used for suctioning-out and ventilation of the crankcase occurs in the intake pipe behind the supercharger device. Only the low pressure which is applied in the intake pipe between the air filter and the supercharger device can be used for this purpose in full load operation.

In partial load operation or even in coasting operation, an intense low pressure, which can be used advantageously for ventilation of the crankcase, exists in the region between the throttle valve and the inlet valve of the internal combustion engine.

Here, as in the following, there is considered as full load operation of the internal combustion engine, an operation with extensively or completely opened throttle valve and/or an operation with a pressure of 0 to 700 mbar, advantageously of 0 to 400 mbar, in the ventilation pipe connected to the intake pipe behind the throttle valve and/or with a pressure of 0 to −200 mbar, advantageously of 0 to −60 mbar, in the ventilation pipe connected to the intake pipe in front of the supercharger device. As partial load operation or no-load operation or coasting operation, there is denoted, here as in the following, a load operation with extensively (partial load operation) or completely (coasting operation) closed throttle valve or an operation at a pressure of 0 to −900 mbar, advantageously of 0 to −750 mbar, in the ventilation pipe connected to the intake pipe behind the throttle valve, and/or an operation with a pressure of 0 to −150 mbar, advantageously of 0 to −60 mbar, in the ventilation pipe connected to the intake pipe in front of the supercharger device. The pressures should be understood respectively relative to the atmospheric external pressure.

It is therefore normal to split the ventilation pipe from the crankcase to the intake duct into two pipes, one of which opens into the intake duct between the air filter and the supercharger device and the other of which opens into the intake pipe behind the throttle valve between throttle valve and inlet valve of the internal combustion engine. With suitable interconnection of the ventilation pipe, now, on the basis of the low pressure present in different sections of the ventilation pipe in different operating states, the crankcase can be reliably ventilated.

The ventilation pipe between the crankcase and the intake duct normally has, in the common part of the ventilation pipe, an oil coarse separator with which oil droplets and oil mist can be separated roughly. In the ventilation partial pipes which connect the common part of the ventilation pipe to the intake pipe in front of or behind the compressor, further oil separators/oil mist separators which contribute to a further improved oil separation can be introduced.

In partial load- or coasting operation, i.e. in the case of a partially or completely closed throttle valve, a very low pressure is present in the intake duct behind the supercharger device and hence a very high pressure gradient (high pressure difference) between the crankcase and the intake duct. In addition, the blow-by gas comprises, in particular in coasting operation, a considerable proportion of unconsumed fuel. Therefore in partial load- or coasting operation, normally a fresh air supply is made possible from the intake duct, typically from the intake pipe in front of the supercharger device, counter to the ventilation direction through the full load ventilation pipe so that the low pressure produced in the crankcase is limited and the blow-by gases are diluted so that the proportion of toxic substances in the exhaust gases is reduced.

In partial load operation, an acceptable mixture of blow-by gases and fresh air is present. However, if the engine switches over into coasting operation, a very high content of uncombusted hydrocarbon compounds occurs suddenly in the blow-by gases which, in the case of immediate further conveyance through the intake duct and engine to the catalyst, would lead to overheating and hence destruction of the catalyst because of combustion of the hydrocarbon compounds. In order to avoid this, it is essential that only specific, namely limited quantities of uncombusted hydrocarbon compounds are conveyed further to the catalyst. In order to counter this, it would be conceivable to dilute the HC-rich exhaust gas greatly via a very high volume flow of fresh air, however in order to stop impermissible pressures occurring here, it would however also be necessary to have an accelerated discharge of this mixture, which would then again lead to a supply of a large quantity of uncombusted hydrocarbons to the catalyst. Hence it is necessary to limit the supply of HC-rich blow-by gases to the engine or catalyst in coasting operation via other measures.

For this purpose, inter alia, in the ventilation partial pipe provided for the partial load- or coasting operation between the oil separator and the intake duct, there can be disposed, between the supercharger device and the inlet valve, a valve which is controlled, in particular electrically, by the engine or valve train of the engine, which valve has a high pressure decrease in coasting operation and hence restricts both the volume flow of throughflowing gases and prevents a breakdown of the intense low pressure in the intake duct towards the crankcase. This and other conventional solutions however generally require a large number of parts and are therefore complex, cost-intensive and assembly-intensive.

It is therefore the object of the present invention to make available a device for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine, and also ventilation systems, cylinder head covers and internal combustion engines including these, which require few individual parts, are easy and economical to produce and assemble and enable a compact construction. In particular, the device according to the invention for separation of oil droplets and/or oil mist is intended to make it possible to control suitably the volume flow of gases in the ventilation pipe to the intake duct of the engine in partial load operation and in coasting operation.

This object is achieved by the device for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine according to claim 1. Furthermore, this object is achieved by the ventilation system according to claim 14, the cylinder head cover according to claim 15 and the internal combustion engine according to claim 16. Advantageous developments of the present invention are given in the dependent claims.

The device according to the invention for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine is inserted as oil separator/oil mist separator, in particular in the ventilation pipe, in particular in the partial ventilation pipe, which opens into the intake pipe behind the supercharger device. It has a valve for control of the gas flow from a pressure side to a suction side of the device.

With an arrangement of this device in a ventilation pipe from a crankcase to an intake pipe of an intake duct of an internal combustion engine, the side orientated towards the crankcase is thereby subsequently termed pressure side and the side orientated towards the intake pipe, suction side, even if, under a few, specific operating conditions of the internal combustion engine, the actual pressure ratios can turn out to be different.

This valve, which has also an oil separation function at the same time, has at least one base plate. The base plate can be configured in one piece or consist of partial plates which are disposed adjacently to each other and successively perpendicular to the plate plane. This base plate has one or more first regions, at least one first gas passage opening for passage of gas from the pressure side to the suction side of the base plate being present in each of the first regions, if present. The present valve is characterised in particular in that, for one or a plurality or all of these first regions, respectively one first valve closure is provided, which can close the first gas passage openings situated in the respective region.

This valve closure is disposed or attached, according to the invention, on the pressure side on the base plate. By means of the pressure-side arrangement of the valve closure, it is possible to control the gas passage through one of the first regions such that the respective valve closure closes the associated first gas passage opening covered by it (or if present, the plurality of gas passage openings present in the respective region), if the low pressure on the suction side relative to the pressure side exceeds a specific limiting value. This leads to the fact that, during transition of the operating state of the engine from full load-, via partial load-, to coasting operation, which is associated with increasing low pressure on the suction side of the device according to the invention, the passage cross-section for the gases to be ventilated from the crankcase into the intake duct is reduced. Hence the pressure decrease is increased increasingly over the device according to the invention during transition from full load-, via partial load-, to coasting operation of the engine so that the crankcase is protected from too low a low pressure and the volume flow is increasingly limited via the device according to the invention. At the same time, a controlled and in particular limited supply of hydrocarbon-rich blow-by gas is made possible to the intake duct or to the catalyst, as a result of which the entry of hydrocarbons into the catalyst is limited, the exhaust gas temperatures are kept within a permissible range and damage to a catalyst can be avoided.

In particular, the device according to the invention can have at least two or more first regions, the valve closures of both or a plurality of first regions having different opening/closing characteristics. As a result of the fact that the valve closures of the individual regions in the device according to the invention close at different pressure differences between the suction side and the pressure side of the device according to the invention, the valve closure close in succession during transition from full load-, via partial load-, to coasting operation. This leads to a successive increase in the pressure decrease over the device according to the invention and a successive reduction in the free passage cross-section of the device according to the invention and hence of the volume flow of blow-by gases flowing over the device. Advantageously, the base plate of the device according to the invention can be provided in addition with a gas passage opening which is unclosable. Alternatively, also at least one of the valve flaps can be provided with an opening which is situated, in flow direction, downstream of one of the gas passage openings covered by it so that the respective gas passage opening is not closed completely even during closure of the valve flap. These gas passage openings of the valve, which are in no case completely closable, ensure a minimum passage of blow-by gases, even in coasting operation at maximum suction-side low pressure. The cross-section of these unclosable openings determines the overall volume flow over the device according to the invention in coasting operation of the engine.

Advantageously, the at least one base plate can be a one-piece component which is produced, for example, in injection moulding technology. As a result, as further components of the device according to the invention, only respectively one further component for the first valve flaps alone, for example designed as resilient tongue, for example this elastic tongue itself, is required. The entire device according to the invention for separation of oil droplets and/or oil mist has therefore very few parts and can therefore be produced and also assembled economically and compactly.

The optional, first resilient tongues according to the invention can respectively have a retaining arm which is mounted resiliently on the valve body, here the base plate, such that the resilient tongue is movable between a first position, in which it closes the first gas passage openings covered by it, and a second position, in which it uncovers the first gas passage openings covered by it.

Each of the resilient tongues can—as already described above—be pretensioned such that, above a predetermined low pressure between the suction side and the pressure side, it closes the respective covered first gas passage openings and opens them above a predetermined positive pressure difference. The pretension can thereby be chosen differently for each resilient tongue.

The retaining arm or the retaining arms can advantageously be configured, according to the invention, such that two different pretensions must be overcome for closing the gas passage openings in succession.

For example, the first pretension can have the effect that, with the initial low but increasing low pressure, the resilient tongue is moved towards the gas passage openings to be closed by this resilient tongue until the resilient tongue abuts against a limit stop region, preferably against a web-like wall of a gas passage opening, without however closing the latter completely. As a result, the gap between the gas passage openings to be closed and the resilient tongue is reduced and thus the pressure decrease over the valve is increased and also the volume flow is reduced.

For this purpose, for example the retaining arm can have a first joint-like bend which is provided between the attachment point of the retaining arm to the valve body and the region of the resilient tongue covering the gas passage openings. Starting from the attachment point, the first bend is produced leading away from the valve body.

A second joint-like bend in the opposite direction to the first bend can be provided between the first bend and the region of the resilient tongue covering the passage openings.

If now the suction-side low pressure increases, then the resilient tongue is deflected firstly, as described above, at the first bend until it abuts against a limit stop element, for example a wall of a gas passage opening.

If the suction-side low pressure is further increased, the resilient tongue is suctioned further in the direction of the gas passage openings around this limit stop element and thereby describes a rotation in the second bend, preferably on or in the vicinity of the limit stop element, so that the resilient tongue closes the gas passage openings.

As a result of the first pretension in the first bend, the resilient tongue is therefore pretensioned at a low intake low pressure by the long lever of the retaining arm up to the mentioned limit stop element. By means of the limit stop, the lever length of the retaining arm is then shortened. For ultimate covering and closing of the gas passage openings, a greater force must then be applied, i.e. an even higher low pressure must be applied. The opening of the gas passage openings is effected with a lower pressure hysteresis relative to the closing pressure required for closing the gas passage openings. As a result, the resilient tongue is thus prevented from uncovering again the gas passage openings only with a very low suction-side low pressure. This enables rapid transition from coasting- to partial load operation.

Furthermore, it is possible to configure the first resilient tongue such that it uncovers the first gas passage openings covered by it in succession during opening. As a result of the successive uncovering of the first gas passage openings, the pressure decrease over the base plate, which is determined by the total cross-section of all respectively uncovered first gas passage openings, is controlled gradually or quasi-continuously.

The first gas passage openings can have, on the side orientated respectively towards the first valve closure, a web-shaped edge which protrudes in a wedge-shape from the base plate and extends circumferentially about the respective gas passage opening as support for the first valve closure. This web-shaped circumferential edge can thereby protrude overall at the same distance circumferentially from the base plate, i.e. be the same height.

Alternatively, the edge can also be flattened in the direction of the mounting of the valve closure so that the valve closure comes to lie on the bevelled edge with pretension.

The protruding edge is in principle suitable as support for the respective valve closure and, in addition, forms a seal between the gas passage opening and the valve closure. Alternatively, also a circumferential embossing, in particular a bead-shaped embossing, can be inserted in the respective valve closure (for example if the latter is manufactured from a metal sheet), in particular in the respective resilient tongues, in order to form a better seal of the respective gas passage opening by the associated valve closure. As circumferential sealing elements, also coatings both of the base plate and of the valve closure are possible. The coatings can thereby be configured partially or also over the entire surface. The valve closure can also be manufactured from a precoated metal sheet.

The first gas passage openings in the first region of the base plate have, in addition to their function of controlling the volume flow of the gas throughflow, in particular also the object of separating oil droplets and/or oil mist from the blow-by gases passing through. This is effected, on the one hand, even in the case of gas passage openings which do not have a further special configuration, since there, because of the narrowing relative to the chamber in front of the gas passage openings, the gas flow is accelerated, or is slowed down at the outlet of the gas passage openings because of the widening. This leads to a separation of oil droplets and/or oil mist situated in the blow-by gas flow. In order to improve the separation performance further, the cross-section of one, of a plurality of or of all of the gas passage openings can also have a nozzle-shaped design.

In a further embodiment of the invention, at least two of the first gas passage openings, preferably two first gas passage openings covered by different resilient tongues, can have different cross-sections of their inlets and/or of their outlets and/or centrally between their inlets and their outlets, in particular with respect to the cross-sectional area and/or cross-sectional shape.

Furthermore, it is possible, in order to improve the separation performance, to dispose, in one, a plurality of or all the first gas passage openings in the base plate, a guiding geometry. This guiding geometry can serve in particular for setting the blow-by gases passing through in a rotational movement about the axial direction/throughflow direction of the respective gas passage opening.

For this purpose, in at least one of the gas passage openings, a for example helical guiding geometry can be disposed, which sets the throughflowing gases in rotation about the axial direction of the gas passage opening. If the valve body has a plurality of partial base plates, then, on the one hand, guiding geometries can be disposed, in the first gas passage openings, only in one of the partial base plates. On the other hand however, guiding geometries can be disposed, also in gas passage openings, disposed successively in flow direction, in partial base plates disposed adjacently to each other, guiding geometries disposed successively in gas flow direction having the same, however preferably opposite, direction of rotation. The guiding geometries can thereby change in their throughflow direction, for example widen. The guiding geometries can be designed, in particular as presented in DE 10 2004 037 157 A1 or in DE 20 2014 002 795 U1. The disclosure content of DE 10 2004 037 157 A1 and of DE 20 2014 002 795 U1 is herewith integrated entirely in the present application, in particular with respect to the configuration and arrangement of the guiding geometries described therein.

In the case of the device according to the invention, in total two or more resilient tongues can be provided in the first region. In the case of two or more resilient tongues, these can have a common attachment region for attachment of the resilient tongues to the base plate. By means of a common attachment region, the attachment region can have a smaller design, material can be saved, space can be made available on the base plate for other components of the valve and/or the valve can have an overall smaller design.

Advantageously, at least two or more resilient tongues can be produced as a one-part element, for example as sheet metal stamped part, in particular from spring-hardened steel. This makes possible, in addition to simpler manufacture, also easier handling and easier assembly, since only one element is present instead of a plurality of individual parts.

In a further advantageous embodiment of the invention, at least one of the resilient tongues is attached resiliently to the base plate via at least one retaining arm such that it is movable between a first position, in which it closes the covered gas passage openings, and a second position, in which it uncovers the covered gas passage openings. As a result, the pressure difference between the suction- and the pressure side of the valve can be adjusted continuously.

At least one of the retaining arms can be attached such that the resilient tongue attached via the retaining arm is movable such that it is removed successively from the gas passage openings covered by it or closes these successively. As a result, the pressure difference and the volume flow between the suction- and the pressure side of the valve can be adjusted more precisely and continuously. As a result, the oil separator can be operated as a function of the volume flow at an operating point with an optimum number of opened/uncovered passage openings.

At least one of the retaining arms can also be attached such that the associated resilient tongue is removed in a tilting movement from at least two gas passage openings or is moved towards these. Also as a result, a predetermined pressure decrease between a suction- and a pressure side of the valve can be adjusted more precisely.

A further advantageous embodiment of the invention provides that two retaining arms are provided for each of the first resilient tongues, which retaining arms extend along two opposite edges of the resilient tongue and enclose between themselves one of the resilient tongues in the positional plane of the resilient tongue, the retaining arms being attached at one of their ends (directly or indirectly) to the base plate and being connected, at their other end, to the resilient tongue, possibly in one piece. In the case of this attachment, the resilient tongue can be removed from the gas passage openings in parallel in the case of a sufficiently high pressure difference and hence all of the covered gas passage openings open at the same time and to the same degree. In other words, when opening the gas passage openings, the spacing between the resilient tongue and the gas passage openings remains essentially constant over the surface area of the resilient tongue. In order that the first resilient tongue is removed evenly from the covered first gas passage openings in this manner, two bending regions or three bending points can be provided. One bending region is situated advantageously in the region of the attachment of the retaining arms to the base plate, i.e. respectively one bending point on each retaining arm. A second bending region is situated advantageously in the region of the one-piece connection between the retaining arms and the resilient tongue. The bending regions extend essentially parallel to each other and possibly parallel to a straight line which connects attachment points of the retaining arms on the base plate to each other.

Preferably, the retaining arms, viewed in radial direction, i.e. directed away from the attachment points of the retaining arms on the base plate, are connected to the resilient tongue behind the last gas passage opening which can be closed by the resilient tongue, possibly in one piece.

At least one of the first resilient tongues can also be attached pretensioned such that it only opens the covered first gas passage openings when the pressure difference between the pressure side and the suction side is above a predetermined threshold value. For this purpose, the resilient tongues or the retaining arms thereof or attachment regions are deformed specifically, preferably in portions, before or during use. For this purpose, preferably the support faces of the resilient tongues or of the attachment regions on the surface of the base plate are bent.

The device according to the invention can have furthermore, in an advantageous embodiment, an additional non-return valve in the outlet pipe of the partial load train subsequent to the gas output chamber which, in the case of high pressure in the section of the intake pipe behind the throttle valve, as can happen for example in full load operation, prevents a return flow of fresh air from this section of the intake pipe to the gas output chamber.

The valves or valve closures of devices according to the invention concern passive elements which in fact can possibly be pretensioned but are controlled individually by the pressure ratios. They manage therefore without additional actuators or electrical or magnetic control units or the like.

In the following, some examples of devices according to the invention, ventilation systems according to the invention, cylinder head covers according to the invention and internal combustion engines according to the invention are now given. The same or similar elements are thereby provided with the same or similar reference numbers and therefore the description thereof is possibly not repeated. In the case of the following examples, each of the examples comprises a large number of additional optional, advantageous developments of the present invention. These can respectively also develop the present invention individually and not only in the illustrated combination. In particular, it is also possible to use combinations of such optional advantageous developments from different subsequent examples together for advantageous development of the present invention, without likewise taking into account respectively all further optional, advantageous developments of the present invention according to the respective examples.

There are shown

FIG. 1 an internal combustion engine according to the invention;

FIG. 2 a device according to the invention as can be used in a valve cover according to the invention or in the internal combustion engine according to the invention according to FIG. 1;

FIGS. 3 to 8 respectively a further example of a device according to the invention.

FIG. 1 shows an internal combustion engine as combustion vehicle in schematic cross-section. The internal combustion engine 1 has a crankcase 2, a cylinder head 3 and also a cylinder head cover/valve cover 4. Furthermore, the internal combustion engine 1 has an intake duct 10 with an air filter 11, an intake pipe 12 with pipe sections 12 a, 12 b and 12 c, a supercharger device 13, for example a turbocharger or a compressor, and also a throttle valve 14. The intake pipe 12 leads, with its section 12 a, from the air filter 11 to the supercharger device 13, with its section 12 b, from the supercharger device 13 to the throttle valve 14 and, with its section 12 c, from the throttle valve 14 to an intake manifold 5 on the cylinder head 3.

In FIG. 1, a ventilation pipe 22 which connects the crankcase 2 to an oil separator 20 is illustrated. In the part of the ventilation pipe 22 opening into the oil separator 20, a coarse oil separator 24 can be disposed. Also in other regions of the ventilation pipe, a coarse oil separator can be provided.

The oil separator 20 has a gas input chamber 21 into which the ventilation pipe 22 opens. The ventilation pipe 22 is illustrated in FIG. 1 as integral element, however it can also lead externally from the crankcase to the oil separator 20.

The gas input chamber 21 serves as settling chamber and forms a pre-chamber in the oil separator 20.

The oil separator 20 has, furthermore, a gas output chamber 25, subsequently termed gas output chamber 25 in full load train, and also a gas output chamber 26, subsequently termed gas output chamber 26 in partial load train. Both gas output chambers 25 and 26 are connected to the gas input chamber 21 so that the blow-by gases can flow from the ventilation pipe 22 via the gas input chamber 21 into the gas output chambers 25 and 26.

Between the gas input chamber 21 and the gas output chambers 25 and 26 or at the beginning of the gas output chambers 25 and 26, devices respectively for separation of oil droplets and oil mist are disposed. These devices are flowed through by the blow-by gases, starting from the gas input chamber 21, in full load-, or partial load-, and coasting operation, oil droplets and oil mist being separated from the throughflowing blow-by gases.

The gas output chamber 25 in full load train is connected via a first output pipe 15 to the section 12 a of the intake pipe 12. It is also possible to design the gas output chamber 25 itself as part of this first output pipe 15. The gas output chamber 26 is connected via a second output pipe 16 to the section 12 c of the intake pipe 12. Here also, the gas output chamber 26 can also be designed as part of the second output pipe 16.

The invention now relates essentially to the device 28 for separation of oil droplets/oil mist which is disposed in FIG. 1 in the output chamber 26 as device according to the invention for separation of oil droplets and/or oil mist from blow-by gases.

The device according to the invention has a valve 30 for control of the gas flow from the pressure side to the suction side of the device in partial load train. The pressure side, in partial load train, is the side orientated toward the crankcase 2, whilst the suction side is the side orientated towards the intake duct 10. The valve 30 according to the invention has a base plate 35 which comprises, in at least one first region, first gas passage openings for passage of gas from the pressure side to the suction side. As is explained later, the device according to the invention in FIG. 1A has two such first regions which respectively comprise separate first gas passage openings. For groups of gas passage openings, respectively one valve flap is disposed on the pressure side on the respective base plate. Each of these valve flaps is pretensioned such that it closes, with sufficient low pressure in the gas output chamber 26, one, a plurality or all of the gas passage openings covered by it.

In the pipe 16, a non-return valve 6 is disposed subsequent to the gas output chamber 26, which valve, in the case of high pressure in section 12 c of the intake pipe 12, as can occur for example in full load operation, prevents return flow of fresh air from section 12 c to the gas output chamber 26.

In FIG. 1A, the internal combustion engine is now illustrated in partial load operation state with an opened non-return valve 6. In the latter, the valve flap is opened in one of the first regions in the device according to the invention and, in another region, the valve flap is closed. As a result, only the gas passage openings in the first-mentioned region are available for passage of the blow-by gases.

In FIG. 1B, the same internal combustion engine is illustrated in coasting operation. In coasting operation, the valve flaps are in a closed state in both regions so that the associated gas passage openings are no longer available for further conveyance of the blow-by gases and the fresh air supplied for scouring. As is explained later, a further, second gas passage opening, which is unclosable, is situated however for example in the base plate. This is sufficient to ensure adequate ventilation of the crankcase in coasting operation since the non-return valve 6 is opened at the same time. On the basis of the small cross-sectional area thereof, it produces a very high pressure decrease so that the crankcase is protected from the very high low pressure in the partial pipe 12 c of the ventilation pipe 12 and, at the same time, the volume flow of throughflowing gases, in particular the volume flow of blow-by gases, with a high proportion of uncombusted hydrocarbons, is limited.

FIG. 1C shows the same internal combustion engine in full load operation. In full load operation, a high pressure is applied in the partial pipe 12 c, whilst a low pressure is present in the partial pipe 12 a. On the other hand, also the volume flows of blow-by gases from the crankcase are very high in full load operation. In this case, the non-return valve 6 closes the pipe 16 so that the high pressure in the partial pipe 12 c does not act on the oil separator 20. On the other hand, the low pressure in the partial pipe 12 a suffices to suction off the blow-by gases in full load operation via the gas output chamber 25.

FIGS. 1C, 1A and 1B illustrate, in this sequence, also the development of the states of the device according to the invention in transition from full load operation, via partial load operation, to coasting operation. Whilst in full load operation of FIG. 1C the non-return valve 6 is closed and the valve flaps of the first gas passage openings are opened, the non-return valve 6 in the ventilation pipe 16 is opened in the case of suitable pressure ratios during transition into partial load operation so that the blow-by gases can be suctioned off completely via the completely opened gas passage openings in the base plate 35. With further decreasing power of the engine, i.e. in the further transition to partial load operation, firstly a first valve flap is then closed, see FIG. 1A, before, with further decreasing power and transition to coasting operation, also the second valve flap is closed, see FIG. 1B.

In total, it is possible, due to the device according to the invention, disposed in an internal combustion engine as in the present FIG. 1, also to enable, in coasting operation of the internal combustion engine, sufficient suctioning-off of the blow-by gases without however supplying too large a quantity of uncombusted hydrocarbons to the catalyst.

FIG. 2 now shows a device according to the invention in partial drawings 2A to 2E. This has two partial base plates 35 a, 35 b which together form the base plate 35.

The partial base plates 35 a and 35 b have regions assigned to each other which have respectively four passage openings 40, 40′, 40 b, 40 b′. These passage openings in both partial base plates 35 a and 35 b are disposed in pairs flush with each other, so that they enable a gas passage from the one side of the double-plate arrangement to the other side of the double-plate arrangement. In each of the regions, four gas passage openings are disposed. These gas passage openings 40 are closable respectively by a valve flap 50, 50′ disposed on the pressure side. Each of the valve flaps 50, 50′ has respectively one resilient tongue 51, 51′ which is mounted, on one side, via a retaining arm 57 or 57′ on an attachment element 56 or 56′ on the pressure-side partial base plate 35 a. The retaining arms have first bending points 58 or 58′ and second bending points 59 or 59′ (see FIG. 2D) so that the resilient tongue 51 or 51′ can be lowered in a planar manner onto the gas passage openings 40 or 40′ and consequently closes these.

The gas passage openings 40, 40′ have a respectively circumferential web 41, 41′, the webs of the gas passage openings 40, 40′ being connected together to form a block in respectively one region, which block protrudes from the plane of the partial base plate 35 a.

As is shown in FIG. 1C, the valve 6 is closed in full load operation so that the blow-by gases are supplied completely via the full load train, i.e. the oil separator, not described further, of the full load train and the chamber 25 and the output pipe 15 to the intake duct 10. Hence the same pressure prevails on both sides of the valve 30, the resilient tongues 51 or 51′ are hence in equilibrium in full load operation. FIG. 2A makes it clear that the two retaining arms 57 and 57′ have different angles and the two resilient tongues 51 and 51′ have different spacings relative to the surfaces of the webs 41. This is achieved via a different pre-deformation of the retaining arms 57 or 57′. As a result, it becomes clear that the two resilient tongues 51 and 51′ are provided with different pretensions.

The corresponding gas passage openings in the partial base plate 35 b likewise have a circumferential web which protrudes from the surface of the partial base plate 35 b, forming a common protruding block in the same manner.

Adjacent to both regions with respectively four gas passage openings 40 or 40′ are further gas passage openings 60, 60′ or 60 b, 60 b′ in the plane of the partial base plates 35 a or 35 b, which openings extend likewise over the entire arrangement of the partial base plates 35 a, 35 b from the pressure side thereof to the suction side. These gas passage openings 60, 60′, 60 b, 60 b′ are unclosable so that they ensure furthermore a minimum gas throughput in coasting operation, even with closure of both valve flaps 50, 50′.

FIG. 2A represents a state in which both valve flaps 50, 50′ are opened corresponding to FIG. 1C.

FIG. 2B represents a state in which the resilient tongue 51′ is supported on the associated gas passage openings 40′ covered by it and thus the valve flap 50′ is closed. The adjacent valve flap 50 is opened, however, because of the higher applied pressure, the spacing between the surface of the block and the valve flap 50 being smaller than in the state illustrated in FIG. 2A. The state shown in FIG. 2B corresponds to FIG. 1A in partial load operation.

FIG. 2C shows a state in which both valve flaps 50, 50′ close the assigned gas passage openings 40, 40′ covered by them. In this way, only the gas passage openings 60, 60′ or 60 b, 60 b′ are still available for a gas passage of blow-by gases, mixed in particular with (little) fresh air, with a high proportion of uncombusted hydrocarbons from the suction side to the pressure side. These ensure the required ventilation of the crankcase in coasting operation of the internal combustion engine and, at the same time, limit the volume flow via the valve 30 and hence the supply of uncombusted hydrocarbons to the catalyst.

The resilient tongues, 51, 51′ are pretensioned such that they are opened without applying a pressure difference between the pressure side (at the top in the drawing) and the suction side (at the bottom in the drawing). Only if the low pressure applied on the suction side exceeds a threshold value (i.e. the pressure on the suction side decreases greatly), is the resilient tongue 51′, as shown in FIGS. 2A to 2C, moved to the surface of the gas passage openings 40′ and closes these. If the low pressure on the suction side increases further and exceeds a further threshold value, then the resilient tongue 51 also closes the gas passage openings 40. The resilient tongues are therefore configured such that they transition into the closed state in the case of different low pressures on the suction side of the valve 30. This enables gradual closing of the gas passage openings and consequently enables gradual adaptation of the blow-by volume flow via the valve 30 to the variable low pressure ratios on the suction side of the valve 30. The use of more than two valve flaps enables finer graduation of the switching behaviour of the valve 30 and control of the pressure of the blow-by gas.

FIG. 2D shows a plan view on the partial base plate 35 a. The resilient tongues 51, 51′ are mounted on attachment elements 56 or 56′ via retaining arms 57 or 57′. The retaining arms 57 or 57′ have first bending points 58, 58′ and second bending points 59, 59′. With the help of these bending points, a movable mounting of the resilient tongues on the partial base plate 35 a is possible. In the gas passage openings 60, 60′, guiding geometries respectively which direct the blow-by gas flow flowing through these gas passage openings are situated.

In FIG. 2E, a plan view on the partial base plate 35 b, i.e. a view from below on the valve 30 in FIG. 2A, is illustrated. In the gas passage openings 40 b, 40 b′ and also in the additional gas passage openings 60 b, 60 b′, there are likewise situated respectively guiding geometries which direct the blow-by gas flow flowing through the gas passage openings.

These described guiding geometries are denoted with 42, 42 b, 42 b′, 42 b″ and, in the present example of FIG. 2, have the shape of a half right- or left screw.

As a result, the gases guided through the gas passage openings are set in a rotational movement, which reinforces the separation performance of the respective gas passage openings 40 b, 40 b′, 60, 60′, 60 b and 60 b′. A particularly high separation performance is achieved if the guiding geometries in the gas passage openings 60, 60′ and also 60 b, 60 b′ are configured such that the direction of rotation of the gases changes abruptly during transition from the gas passage openings 60, 60′ into the gas passage opening 60 b, 60 b′. This can be effected by the direction of rotation of the associated guiding geometries in the gas passage openings 60, 60′ being in opposite directions to the direction of rotation of the guiding geometries in the gas passage openings 60 b, 60 b′. Such guiding geometries can also be disposed in the gas passage openings 40, 40′.

FIG. 3 shows, in the partial FIGS. 3A to 3E, a further embodiment of a valve 30. In contrast to the embodiment in FIGS. 2A to 2E, now the resilient tongues 51, 51′ are mounted respectively via two retaining arms 57, 57′. This enables uniform guidance of the resilient tongues 51, 51′. The two retaining arms 57 of the block of gas passage openings 40, disposed further to the left, are both the same and in fact are more strongly pre-deformed than the two retaining arms 57′ of the block of gas passage openings 40′, disposed further to the right. As a result, the left resilient tongue 51 has greater pretension than the right resilient tongue 51′.

In contrast to FIG. 2, now merely the gas passage openings 40 b′ have guiding geometries, whilst the gas passage openings 40 b and also 60, 60′, 60 b, 60 b′ comprise no corresponding guiding geometries.

FIG. 4 shows a further embodiment of the valve 30. In contrast to FIG. 2, each region with gas passage openings now has eight gas passage openings. The associated resilient tongues 51, 51′ are manufactured as a one-part component and are mounted on a common central web. This central web 55 is attached to attachment means 56, 56′, for example pins 56, 56′ protruding out of the partial base plate 35 a. The retaining arms 57 have a substantially narrower configuration than the retaining arms 57′ so that the retaining arms 57, in the case of the same pre-deformation of the retaining arms 57 and 57′, which is not explicitly detectable here in the closed state, have less pretension.

Furthermore, the partial base plate 35 a has an unclosable gas passage opening 60.

FIG. 5 shows a further embodiment of a valve according to the invention, FIG. 5A again showing a plan view on the valve 30, i.e. a plan view on a base plate 35, FIG. 5B a side view and FIG. 5C a view from below of the valve 30, i.e. a plan view on the base plate 35.

Also in this embodiment, two regions which have respectively eight gas passage openings in the base plate 35 are provided. The resilient tongues 51, 51′ are disposed offset relative to each other so that the constructional space on the base plate 35 is well exploited.

Both valve closures 50, 50′ have respectively only one retaining arm 57, 57′. The retaining arm 57′ is essentially narrower and configured with a greater radius than the retaining arm 57 so that the retaining arm 57′, in the case of the same pre-deformation of the retaining arms 57 and 57′, which is not explicitly detectable here in the plan view in the closed state, has less pretension than the retaining arm 57.

In contrast to the preceding embodiments, one of the resilient tongues, here the resilient tongue 51, has an opening 53 which is disposed directly above a gas passage opening in the partial base plate 35 a and a gas passage opening situated thereunder in the partial base plate 35 b. The corresponding gas passage opening in the partial base plate 35 b is denoted with X in FIG. 5C. The gas passage opening 53 in the resilient tongue 51 prevents the gas passage opening situated thereunder from being able to be closed. This gas passage opening serves therefore for maintaining a minimum gas throughput in coasting operation, in the same manner as the unclosable gas passage openings 60, 60′, 60 b, 60 b′ in the other preceding examples.

FIG. 5B illustrates the valve 30 in the closed state of both valve flaps 50, 50′ in a side view on the side of the valve 30 pointing downwards in FIG. 5A. Both resilient tongues 51, 51′ are pretensioned and protrude externally upwards away from the base plate 35. The groups of passage openings 40, 40′ have, on the pressure side pointing upwards, respectively one web 62 or 62′ which extends circumferentially about the entire group and forms respectively a support for the resilient tongue 51 or 51′. This web 62 or 62′ has, along the circumference thereof, a changing, increasing height, namely with increasing distance from the respective attachment means 56 or 56′. If the angles at which the pretensioned resilient tongues 51, 51′, on the one hand, and the upper edge of the web 62 or 62′, on the other hand, extend relative to the plane of the base plate 35 are compared, then a greater angle results for the resilient tongues 51, 51′. This means that the resilient tongues 51, 51′ are bent before complete closure of the passage openings 40, 40′ against the pretension of the resilient tongues 51, 51′.

FIG. 6 shows a further embodiment of a device according to the invention with reference to a side view comparable to FIG. 5B, likewise in the opened state. The resilient tongues 51, 51′ are designed here without pre-deformation. The pretension of the flap of the resilient tongues 51, 51′ is produced via the web 62, 62′ which, similarly to the embodiment of FIG. 5, has a circumferentially changing height, here the height reducing with increasing spacing relative to the attachment means 56, 56′ of the associated resilient tongue 51, 51′. Upon closure of the resilient tongues 51, 51′, these abut firstly against the portion of the edge 62, 62′ which points towards the centre of the illustrated side view and, in the further course, against the pretension which is produced from the straight shape of the spring-hardened steel plate of the resilient tongues 51, 51′, unwind on the edge and thus close the passage opening 40, 40′.

Furthermore, the resilient tongues 51, 51′ have sealing elements 69 which extend circumferentially on the lower side thereof and are configured as elastomer beads.

FIG. 7 shows, in the partial Figures A, A′, B, B′, C, C′, a further embodiment of a device according to the invention with reference to side views A, B and C and also corresponding plan views A′, B′, C′. In FIGS. 7A, 7A′, the valve is illustrated in the completely closed state, in FIGS. 7B, 7B′ in a specifically pretensioned state and, in FIGS. 7C, 7C′, in an opened state.

FIG. 7 shows a valve 1 with gas passage openings 40, 60 a and 60 b. The gas passage openings 60 a and 60 b are unclosable and therefore serve as bypass from the pressure side to the suction side of the valve 1. The gas passage opening 40 is closed by a resilient tongue 51 as valve flap 50 in FIGS. 7A, 7A′. The resilient tongue 51 is connected to the base plate 35 of the valve 1 via a retaining arm 57 on an attachment element 56.

The retaining arm 57 has, between the attachment point 56 and the resilient tongue 51, two bending points 70, 71 (bends), at which the retaining arm 57 is bent in different directions. In FIGS. 7C, 7C′, which show the valve in the opened state in the case of a small pressure difference between the pressure side and the suction side of the valve 1, the resilient tongue 51 is at a spacing completely from the gas passage opening 40 or the wall thereof. As a result, a large gap between the wall of the gas passage opening 40 and the resilient tongue 51 is produced so that a large volume flow can flow through the gas passage opening 40 in the case of a small pressure difference.

If the low pressure on the suction side of the valve 1 is increased, which is present here in the drawing plane below the base plate 35, then the resilient tongue 51 is suctioned towards the gas passage opening 40. This takes place until the resilient tongue 51 abuts on the wall of the gas passage opening 40 with the region situated opposite the gas passage opening 40. In fact the flow gap between the gas passage opening 40 and the resilient tongue 51 is thereby reduced so that the volume flow which can flow through this gap is reduced. At the same time, the flow resistance decreasing over the valve 1 is increased so that in fact a crankcase is protected here if necessary from low pressure which is too low in the intake duct of an internal combustion engine.

If the low pressure on the suction side of the valve 1 increases further, then, finally, as illustrated in FIGS. 7A, 7A′, the resilient tongue 41 is suctioned towards the surface of the wall of the gas passage opening 40 so that the latter is completely closed by the resilient tongue 51. As gas passage openings, there remain then merely the unclosable openings 60 a and 60 b which ensure sufficient suctioning of the blow-by gases out of the crankcase and sufficient oil separation. In order to close the gas passage opening 40 completely by the resilient tongue 51, bending of the region of the resilient tongue 51 situated opposite the gas passage opening 40 is effected about a bending point 71.

Upon reducing the low pressure on the suction side of the valve 1, now the previously described steps for closing the gas passage opening 40 are run through in reverse sequence to FIGS. 7A, 7A′, via FIGS. 7B, 7B′, to FIGS. 7C, 7C′. In fact a low pressure difference thereby suffices for opening of the valve flap 50.

FIG. 8 illustrates, in a side view and a plan view, a further device according to the invention with a valve 1 and gas passage openings 40, 60 a and 60 b. The gas passage openings 40, 60 a and 60 b are thereby designed as in the preceding embodiment. The embodiment of FIG. 8 differs from that of FIG. 7, on the one hand, by the valve flap 50 here being embedded directly in a continuation 63 of a web 41 which extends circumferentially about the gas passage openings 40. This continuation 63 is formed in one piece and materially uniform with the base plate 35, but has a greater total height than the webs 41. The resilient tongue 51 is thereby embedded at a rising angle coordinated to the spacing from the edge so that, in the opened state illustrated here, a pretension is produced. The switching behaviour of the valve 30 hence corresponds here extensively to that of the valve from the embodiment of FIG. 7 between the states of partial FIGS. 7A and 7B so that, here also, a low pressure difference leads to opening of the valve flap 50. 

1-16. (canceled)
 17. A device for separation of oil droplets and/or oil mist from blow-by gases of an internal combustion engine, having a valve for control of the gas flow from a pressure side to a suction side of the device, the valve having at least one base plate, comprising: at least one first region of the at least one base plate, there being disposed in each of the first regions at least one first gas passage opening for passage of gas from the pressure side to the suction side of the base plate and also, on the pressure side of the at least one base plate, and at least one first valve closure for pressure-side closure of the at least one first gas passage opening.
 18. The device according to claim 17, wherein the first valve closure of each of the first regions has a pretension such that it closes the first gas passage openings overlapped by it when the low pressure of the suction side relative to the pressure side exceeds a predetermined low pressure in magnitude.
 19. The device according to claim 17, wherein at least two first regions of the at least one base plate, wherein the predetermined threshold values of the valve closure of at least two of the at least two first regions are different from each other.
 20. The device according to claim 17, further comprising a second region of the at least one base plate, which is disposed adjacent to the side of the first region, and in which at least one second unclosable gas passage opening for passage of gas from the pressure side to the suction side of the valve is disposed.
 21. The device according to claim 17, wherein at least one of the first valve closure has a first resilient tongue which is disposed on the pressure side of the base plate.
 22. The device according to claim 21, wherein at least one of the first resilient tongues is attached resiliently to the base plate via at least one retaining arm such that it is movable between a first position, in which it uncovers the first gas passage openings overlapped by it, and a second position, in which it closes the first gas passage openings overlapped by it.
 23. The device according to claim 22, wherein the retaining arm has, between its attachment to the base plate and the region of the resilient tongue overlapping the gas passage opening, at least two bends which are opposite each other.
 24. The device according to claim 21, wherein at least one of the first resilient tongues is configured such that at least one of the first gas passage openings overlapped by it is unclosable by the first resilient tongue.
 25. The device according to claim 21, wherein at least one of the first gas passage openings on the pressure side of the base plate has an edge which protrudes in a web-shape from the base plate and extends circumferentially about the first gas passage opening as support for the first resilient tongue covering the first gas passage opening.
 26. The device according to claim 25, wherein the circumferential edge is circumferentially the same height or is flattened in the direction of the mounting of the first resilient tongue or has an additional sealing element which extends circumferentially on the edge.
 27. The device according to claim 21, wherein at least one of the first resilient tongues has an embossing which extends circumferentially about at least one of the first gas passage openings.
 28. The device according to claim 27, wherein the at least one embossing is a bead-shaped embossing or a circumferential sealing element.
 29. The device according to claim 17, wherein at least one of the at least one first gas passage openings has a narrowed cross-section which acts as oil separator element.
 30. The device according to claim 17, wherein in at least one of the at least one first gas passage openings, there is disposed a flow-deflection- and -guiding element as oil separator element, in particular a helix-shaped element.
 31. The device according to claim 30, wherein the oil separator element is a helix-shaped element.
 32. A ventilation system for ventilation of the crankcase of an internal combustion engine comprising: an intake duct with a compressor and a throttle valve, having an oil separator with a gas input chamber and at least two separate gas output chambers connected thereto, a first ventilation pipe for connecting the crankcase of the internal combustion engine and the gas input chamber of the oil separator, a first output pipe for connecting the first gas output chamber to the intake duct of the internal combustion engine before the compressor, and a second output pipe for connecting the second output chamber to the intake duct of the internal combustion engine behind the throttle valve, wherein in the second gas output chamber, there is disposed a device for separation of oil droplets and/or oil mist. 